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Optical designs for astronomy involve implementation of active optics and adaptive optics from X-ray to the infrared. Developments and results of active optics methods for telescopes, spectrographs and coronagraph planet finders are…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Gerard R. Lemaitre

Angular anisotropy techniques for cosmic diffuse radiation maps are powerful probes, even for quite small data sets. A popular observable is the angular power spectrum; we present a detailed study applicable to any unbinned source skymap…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Sheldon S. Campbell

The number of galaxies with measured redshifts > 1 is at present rapidly increasing, allowing for measurements of their correlation function. The correlations function is measured in redshift space, as a function of angular separation and…

Astrophysics · Physics 2009-10-31 Vibhat Nair

The direct detection and imaging of exoplanets requires the use of high-contrast adaptive optics (AO). In these systems quasi-static aberrations need to be highly corrected and calibrated. In order to achieve this, the pupil-modulated…

Instrumentation and Methods for Astrophysics · Physics 2022-05-25 Nicolas Dubost , Nazim Ali Bharmal , Marc Dubbeldam , Richard M. Myers

With the aim of paving the road for future accurate astrometry with MICADO at the European-ELT, we performed an astrometric study using two different but complementary approaches to investigate two critical components that contribute to the…

The image degradation produced by atmospheric turbulence and optical aberrations is usually alleviated using post-facto image reconstruction techniques, even when observing with adaptive optics systems. These techniques rely on the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 A. Asensio Ramos , A. Lopez Ariste

In this paper, we discuss the benefits of ground-based, adaptive optics (AO) aided observations for star formation research. After outlining the general advantages, we present results obtained during the ALFA science demonstration programme…

Astrophysics · Physics 2015-06-24 M. Feldt , M. Kasper , F. Eisenhauer , S. Hippler

We study the 2D motion of colloidal dimers by single-particle tracking and compare the experimental observations obtained by bright-field microscopy to theoretical predictions for anisotropic diffusion. The comparison is based on the…

We present an analytical derivation of the on-axis performance of Adaptive Optics systems using a given number of guide stars of arbitrary altitude, distributed at arbitrary angular positions in the sky. The expressions of the residual…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 E. Tatulli , A. N. Ramaprakash

A new era of ground-based observations, either in the infrared with the next-generation of 25-40m extremely large telescopes or in the visible with the 8m Very Large Telescope, is going to be assisted by multi-conjugate adaptive optics…

Instrumentation and Methods for Astrophysics · Physics 2022-09-05 Giulia Carlà , Lorenzo Busoni , Cédric Plantet , Guido Agapito , Carmelo Arcidiacono , Paolo Ciliegi

The Chinese Space Station Survey Telescope (CSST) presents significant potential for high-precision astrometry. In this study, we show that the point spread function (PSF) modeled by the discrete PSF with Multi-Gaussian function can…

Instrumentation and Methods for Astrophysics · Physics 2025-08-15 Jialu Nie , Peng Wei , Zihuang Cao , Yibo Yan , Chao Liu , Hao Tian , Xin Zhang , Haijun Tian

We describe results from the first astronomical adaptive optics system to use multiple laser guide stars, located at the 6.5-m MMT telescope in Arizona. Its initial operational mode, ground-layer adaptive optics (GLAO), provides uniform…

Boltzmann transport problems often involve heavy streaming, where particles propagate long distance due to the dominance of advection over particle interaction. If an insufficiently refined non-rotationally invariant angular discretisation…

Numerical Analysis · Mathematics 2019-11-06 S. Dargaville , R. P. Smedley-Stevenson , P. N. Smith , C. C. Pain

We investigate the role of asymmetries in the line spread function of the 2-degree field spectrograph and the variations in these asymmetries with the CCD, the plate, the time of observation and the fibre. A data-reduction pipeline is…

Astrophysics · Physics 2009-11-10 N. F. Martin , R. A. Ibata , B. C. Conn , M. J. Irwin , G. F. Lewis

We make the in-orbit calibration to the point-spread functions (PSFs) of the collimators of the Hard X-ray Modulation Telescope with the scanning observation of the Crab. We construct the empirical adjustments to the theoretically…

Instrumentation and Methods for Astrophysics · Physics 2020-02-05 Yi Nang , Jin-Yuan Liao , Na Sai , Chen Wang , Ju Guan , Cheng-Kui Li , Cheng-Cheng Guo , Yuan Liu , Jing Jin , Xiao-Bo Li , Shu Zhang , Shuang-Nan Zhang

Current and future imaging surveys will measure cosmic shear with statistical precision that demands a deeper understanding of potential systematic biases in galaxy shape measurements than has been achieved to date. We use analytic and…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-15 Joshua E. Meyers , Patricia R. Burchat

Scene viewing is used to study attentional selection in complex but still controlled environments. One of the main observations on eye movements during scene viewing is the inhomogeneous distribution of fixation locations: While some parts…

Neurons and Cognition · Quantitative Biology 2018-11-14 Hans A. Trukenbrod , Simon Barthelmé , Felix A. Wichmann , Ralf Engbert

Accurate knowledge of the telescope's point spread function (PSF) is essential for the weak gravitational lensing measurements that hold great promise for cosmological constraints. For space telescopes, the PSF may vary with time due to…

Astrophysics · Physics 2009-11-13 Zhaoming Ma , Gary Bernstein , Alan Weinstein , Michael Sholl

While the formulation of most data assimilation schemes assumes an unbiased observation model error, in real applications, model error with nontrivial biases is unavoidable. A practical example is the error in the radiative transfer model…

Methodology · Statistics 2016-11-17 John Harlim , Tyrus Berry

This Point spread function (PSF) plays a crucial role in many computational imaging applications, such as shape from focus/defocus, depth estimation, and fluorescence microscopy. However, the mathematical model of the defocus process is…

Computer Vision and Pattern Recognition · Computer Science 2022-09-20 Renzhi He , Yan Zhuang , Boya Fu , Fei Liu